WASHINGTON (AP) — Architects and engineers are still in; accountants, doctors and lawyers remain out — mostly. New rules floated by the Trump administration lay out what kinds of businesses can take a 20 percent deduction against income taxes under the new tax law.

With the proposed rules issued Wednesday, the Treasury Department and the IRS had worked for six months to bring clarity to Congress' blueprint. But as with many aspects of the sweeping Republican tax law hustled through Congress last year, the requirements for the millions of "pass-through" businesses to score generous tax breaks are stunningly complex.

Business owners earning over certain income levels, for example, are excluded, as are companies that are organized in certain ways or that lease their equipment rather than own it.